Process for surfacing sheet glass



Jan. 31, 1933. J. c. BLAIR 1,895,908

PRQCESS FUR SURFACING SHEET GLASS I Filed Jan. 10, 1929 2 Sheets-Sheet 1 amnion James C. Blair Jan. 31, 1933. J. c. BLAIR 1,895,908

PROCESS FOR SURFACING SHEET GLASS I Filed Jan. 10, 1929 2 Sheets-Sheet 2 gwuvntoz Jbmes 6.5/01! Patented Jan. 31, 1933 UNITED STATES PATENT OFFICE JAMES C. BLAIR, OF TOLEDO, OHIO, ASSIGNOR TO LIIBBEY-OWENS-FORD GLASS COM- PANY, OF TOLEDO, OHIO, A. CORPORATION OF OHIO- PROGESS-FOR 'SURFACIN'G SHEET GLASS Application filed January 10, 1929. Serial No. 331,553.

This invention relates to an improved process for grinding and polishing glass sheets or plates by .a so-called continuous operation.

In the surfacing of sheet glass by such a process, a plurality of glass supporting tables or trucks are arranged end to end, preferably in abutting relation, and passed in a definite substantially horizontal path, to carry the glass sheets mounted thereupon, first beneath a series of grinding units and then beneath a series of polishing units. The grinding and polishing units are arranged in succession to one another and ordinarily, they execute their working movements without changing their relative positions. While the grinding units may continue their operations practically uninterrupted, interruptions in the operation in the polishing units are unavoidable since they must be temporarily stopped and removed'for the purpose of washing, cleaning or interchanging the polishing pads or felts.

The present invention has for its object to provide a process wherein the removal of the polishing units from the polishing line for the purpose of cleaning and/or repairing may be easily and quickly effected and in such a manner that the polishing operations will not be subjected to any mate rial interruption. According to this invention, the grinding units are adapted to be arranged as heretofore and to perform their working movements without changing their relative positions. However, the polishing units are adapted to be separated or divided into a plurality of groups, each group consisting of a series of units and being spaced from the adjacent groups a distance sufficient to accommodate at least one unit. The

individual polishers of the several groups, while normally maintained stationary in their operative movements, are adapted, at desired intervals, to be given a movement either in the same direction as the movement of the sheets or in a direction opposite to the direction of travel thereof. The polishers are adapted to be moved in asubstantially horizontal direction and in a plane parallel to the surfaces of the sheets being treated ani each polisher is adapted to be successively lifted or removed from and then lowered or replaced in operative position.

The movement of the polishing units is effected when it is desired to remove the polishers for the purposes of cleaning or renewing the polishing pads or felts or repairing the same. Ordinarily, in the continuous system, anywhere from twenty to fifty polishers are arranged in a continuous line and it is a rather difficult matter, upon scratching of the glass sheets, (which may be caused by glass splinters or pieces of glass imbedded in the polishing pads) to accurately ascertain just which of the polishers in the long line is causing the scratching. Therefore, it is necessary that the polishing units be successively removed and the felts thereof cleaned or renewed until the polisher causing the scratching is found. This, of course,'necessitates the expenditure of a considerable amount of time and labor. However, by dividing the polishing units into a a plurality of .spaced groups in accordance with the present invention, it can be easily determined just which group is causing the scratching and since each group may consist of only a small number of polishers, even though the exact polisher causing the scratching may not be known, all of the polishers in any one group can be easily and quickly removed, cleaned and replaced in operative poistion and without materially interrupting the polishing of the glass. Also, it will probably be found that, under ordinary conditions, those polishers of the first one or two groups immediately following the grinders will cause most of the scratching and thus these groups can. be moved prac- I tically continuously, if desired, without in any way affecting the remaining groups.

Upon moving of any one group of polishers, the end polisher at one end of the group is lifted from operative poistion when it reaches a predetermined point in the course of its travel, the same cleaned, and subsequently replaced in operative poistion at the mediately lowered into position at the opposite end of said group such as when it is necessary to repair the removed polisher before it can be replaced in operation.

Other objects and advantages of this in a plurality of trucks or tables mounted upon wheels 11 running upon tracks 12. These tables are adapted to be preferably arranged in abutting end to end relation and to carry the glass sheets 13 mounted thereupon, first beneath a series of grinding units 14 and then beneath a series of polishing units 15, the grinding and polishing units being arranged in succession to one another as illus-' trated in Fig. 3. The tables 10 may be driven in any desired manner such as from a drive pinion or the like 16 meshing with the rack bars 17 secured to the undersides of the tables. The grinding units 14 may be of any preferred construction and are adapted to be maintained stationary during their operative movements.

The polishing units 15 are herein separated or divided into a plurality of groups, two groups herein shown by way of illustration and designatedA and B. While each group is shown as including but three polishmg units, any desired number may be used and also any number of groups may be employed. The first group of polishing units A, when maintained stationary in their operative movements, are adapted to be spaced from the foremost grinder 14' a distance suificient to accommodate at least one unit. This vacant space is designated C, and a second vacant space D is provided between the polishing groups A and B. A similar space will, of course, be provided between other groups which may be used. As above stated, the groups of polishing units are adapted to be normally maintained stationary during the polishing of the glass but are adapted, at intervals, to be given a movement either in a direction with the glass sheets or in a direction opposite to the direction of travel thereof. One type of apparatus by which this may be accomplished is illustrated by way of example in Figs. 1 and 2. As shown in Fi 1, thei -olishin units 15 are preferv g P g ably arranged in pairs opposite one another transversely of the tables, although one or any number of units may be used as found most desirable. Arranged along one side of the lineof tables 10 are a plurality of spaced supporting standards or columns 18, and similar columns or standards 19 are also arranged along the opposite sides of-the transversely extending supporting members 24 carrying bearing parts 25 which receive vertically therethrough the vertical drive spindles 26 of the polishing units.

Each polishing unit includes a horizontal supporting frame 27 secured to the lower end of drive spindle 26 and carrying a plurality of polishing blocks or members 28, each being covered with a polishing pad of felt or the like, and it is" these pads or felts that require washing, cleaning, and interchanging at intervals.

The upper end of each bearing part 25 is bifurcated as shown to provide the spaced horizontally aligned bearings 29 and 30. Mounted upon each carrier 22 is a motor'31 having a shaft 32 which extends transversely of the tables through the aligned bearings 29 and 30 and has its outer end journaled in the bearing 33 supported by the opposite carrier 23. Keyed to the motor shaft 32, intermediate each pair of bearings 29 and 30, is a worm 34 meshing with and driving the worm gear 35 carried at the upper end of the drive spindle 25 of each polishing unit. Thus, upon operation of the motor, the polishing units will be driven in unison. The motor 31 may derive its power from a trolley wire 36 through trolley 37.

In order to effect desired movement of the individual groups of polishing units, there is secured to the under surface of each of the carriers 22 and 23, rack bars 38 with which mesh drive pinions 39 carried by one of the standards 17 and 18. The rack bars are received within recesses 40 formed in the upper A pair of drive pinions 39 is provided for each group of polishers, and when it is desired to effect movement of the polishers in a direction opposite to the direction of movement of the sheets, the drive pinions are mounted at the forward end of the respective groups to rotate in the direction indicated by the arrow in Fig. 2 so as to positively propel the end polishing unit of each group rearwardly, and since the carriers abut one another, the preceding polishers of the several groups will be pushed along the trackways. However, when it is desired to effect movement of the units in the same direction as the travel of the sheets, the drive pinions are mounted at the opposite ends of the respective groups and driven in the opposite direction. Each pair of polishing units may be individually lifted from the glass by means of cables 42 attached to the motor 31 and hearing 33 at their lower ends and to a crane or the like at their upper ends.

According to the present invention and as above stated, the grinding units 1 are maintained stationary in the execution of their operative movements and that while the polishing units are also normally maintained stationary, one or more of the polishing groups are adapted to be moved horizontally at intervals, such as when it is desired to clean or renew the polishing pads or felts as a result of scratching of the glass sheets or for any other reason. This movement of the polishing groups may be either in a direction with the travel of the sheets or in a direction opposite to the direction of movement thereof. When the polishers are executing their working movements while being maintained stationary, they will assume the positions indicated in Fig. 3. That is, the group of polishers A will be spaced from the grinders 14 to provide the vacant space C while the two groups of polishers A and B will be spaced from one another to provide the vacant space D. During polishing, the glass sheets are adapted to be inspected as they pass from beneath each successive group of polishers. Let us assume, therefore, that an inspector, examining the glass between the polishing groups A and B, notes that the glass entering the space D is somewhat scratched. He knows, of course, that the scratching is probably being caused by one of the polishers in group A, although he may not be sure as to just which polisher of this group is causing the trouble. The polishing units of this group are thereupon imparted a movement in a direction opposite to the direction of travel of the glass sheets. Upon such movement, the rearmost polisher will gradually move into the vacant space C as shown in Fig. 4 and when this polisher reaches a predetermined position with respect to the foremost grinder, the said polisher is adapted to be lifted bodily from the glass, the

itated and improved, the po polishing pads thereof washed, cleaned or lnterchanged and the said unit then carried forwardly over the preceding polishers of the group as indicated by the arrows and subsequently lowered upon the glass forwardly over and adjacent the foremost polisher.

As each succeeding polishing unit of the group moves into the space C, it is raised from the glass, the pads thereof treated and the same then replaced at the head of the group in the same manner. As the lifting of the unit, the interchanging or cleaning of the felts and the carrying thereof into the new position at the head of the group may be executed very rapidly, the continuous treatment of the glass is not subjected to any material interruption. In this manner all of the polishers of any one group can within a short time and the scratching of the glass consequently quickly correct/ed. In addition,the polishing of the glass is both facilishing operation be cleaned being more efficiently performed and thequality of finish of the sheet enhanced. When the rearmost polisheris raised from the glass for cleaning another polisher, such as a reserve polisher, can be immediately lowered upon the glass at the forward end of the group to compensate for the polisher removed such as in a case where the removed polisher may require some repair before it can agaln be placed in operation. I

During the movement of the group A, the group B can be maintained stationary or, if desired, can also be moved in a direction opposite to the direction of movement of the sheets. As each 'rearmost polisher of group B enters the space D. it is lifted from the glass, carried forwardly over the preceding polishers and again lowered into position at the head of the group. Also, one or any number of polishing groups can be moved in the same direction as the movement of the sheets or, if preferred, the group A can be moved in a direction opposite to the direction of movement of the sheets and the group B in a direction with the sheets. When moved with the sheets, the polishers of group A are successively lifted from the glass as they enter the space D, the polishing pads thereof cleaned, or renewed and the unit carried rearwardly over the. succeeding polishers and lowered onto the glass at the opposite end of the group. A like space is adapted to be provided at the forward end of each group for successively receivingthe polishers thereof.

As above stated, in the continuous system, probably the first few groups of polishing units immediately following the grinders are most apt to cause scratching of the glass since the polishing pads thereof are most likely to pick up glass splinters or pieces of glass which may remain upon the sheets after the grinding operation. Thus, by dividing the polishers into spaced groups, the first few groups most likely to cause scratching may be substantially continuously moved, if desired, to keep the pads thereof clean and in I this way minimize scratching. This can, of

course, be done without in any way affecting the remaining polishers which would probably not have to be moved nearly so often.

' .ng the sheets in a definite, substantially horizontal path successively beneath a series of grinding and polishing units, dividing the polishing units into a plurality of spaced groups, each including a series of polishers with the space between adjacent groups beg in of a size to accommodate at least one po isher, and in imparting to the polishing units of one or more groups a movement in a substantially horizontal direction independently of the other groups and in a plane parallel to the surfaces of the sheets being treated.

2. The process of grinding and polishing glass sheets or plates, which consists in passing the sheets in a definite, substantially horizontal path successively beneath a series of grinding and polishing units, dividing'the polishing units into a plurality of spaced groups, each including a series of polishers with the space between adjacent groups being of a size to accommodate at least one polisher, in imparting to the polishing units of one or more groups a movement in a substantially horizontal direction independently of the other groups and in a plane parallel to the surfaces of the sheets being treated, and in successively removing the polishers of each moving group from and replacing them in operative position with respect to the glass sheets. i

3. The process of grinding and polishing glass sheets or plates, which consists in passin g'the sheets in a definite, substantially horizontal path successively beneath a series of grinding and polishing units, dividing the polishing units into a plurality of spaced groups, each including a series of polishers with the space between adjacent groups being of a size to accommodate at least one polisher, in imparting to the polishing units of one or more groups a movement independently of the other groups in the direction opposite to the direction of travel of said sheets, and. in successively removing the polishers of each moving grpup and replacing them in operative position with respect to the glass sheets.-

4;. The process of grinding and polishing glass sheets or platesfinwhich consists in passor more groups a movement independently of the other groups in a substantially horizontal dlIGCtlOIl and in a plane parallel to'the surfaces of the sheets being treated, lifting the polishing unit at one end of each moving group out of operative position when it reaches a predetermined point in the course of its travel, and in inserting a polishing unit at the opposite end of each moving group to compensate for the polishing unit removed.

5. The process of grinding and polishing lass sheets or plates, which consists in passing the sheets in a definite, substantially horizontal path successively beneath a series of grinding and polishing units, dividing the polishing units into a plurality of spaced groups, each including a series, of polishers with the space between adjacent groups being of a size to accommodate at least one polisher, normally maintaining the polishing units of each group stationary in their operative movements, in then imparting to the polishing units of one or more groups a movement independently of the other groups in asubstantially horizontal direction and-in a plane parallel to the surfaces of the sheets being treated, successively lifting the-end polishing unit from one end of each moving group when it reaches a predetermined point in the course of its travel, cleaning and/or repalring the polishing unit removed, carrying 1t over the remaining polishing units of the respective group in a direction opposite to the direction of travel thereof, and then lowering the polisher into operative position upon the glass at the end of the group remote from the end from which it was removed.

'Signed at Toledo, in the county of Lucas and State of Ohio, this 5th day of J anuary JAMES C. BLAIR. 

